During operation, heavy equipment such as that used in the mining industry, for example large mill gears, shovels and draglines, becomes coated with soil such as surette and lube grease and residues from the processing operations employing such equipment. In order to prolong the life of such equipment it is necessary to provide regular cleaning so that preventive maintenance may be carried out.
In the past, when equipment such as large mill gears were to be cleaned for regular maintenance or inspection procedures it was generally necessary to shut down the operation and manually clean the equipment with scrapers and rags. This procedure could take a crew of as many as five men up to a week to properly clean the mill gears. In order to reduce the downtime associated with such a method, an alternative chemical method for removing surette and lube grease prior to inspection, welding or nondestructive testing of shovel and drag line components and large mill gears was developed. This chemical method allowed cleaning during at least partial use of the mill gears and for this reason had a major advantage over earlier cleaning techniques. In order to provide adequate solvency for cleaning, this chemical method utilized methylenechloride based products which have a major disadvantage in that they are toxic and require persons using such compositions to wear self-contained breathing apparatus. Additionally, if the methylenechloride solutions contacted any painted surfaces, such contact could result in the rapid removal of the paint from the surface. Therefore, although this method allowed cleaning during use of the mill gears, the personnel preparation time and level of care required result in a cleaning technique which is not satisfactory. It must be recognized that the cleaning of large mill gears must protect the gears against the extreme pressure normally encountered therein. Furthermore, a less toxic and less hazardous cleaner is required which will still allow effective cleaning with little downtime.